RU2575961C2 - Method of regulation of volume flow of heating and/or cooling medium flowing through heat exchangers in heating or cooling unit - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: method of regulation of volume flow of the heating and/or cooling medium flowing through heat exchangers in the heating or cooling unit, consists in change of target difference of temperatures of medium in the supply and return pipelines of separate heat exchangers. Heat exchangers are assigned by different priorities proceeding from the difference of medium temperatures, specific to this installation, in the supply and return pipelines are appointed. For heat exchangers with lower priority the large target difference of medium temperatures in the supply and return pipelines is provided. For heat exchangers with higher priority the smaller target difference of medium temperatures in the supply and return pipelines is allowed. When using the heat exchanger with higher priority at smaller difference of medium temperatures in the supply and return pipelines the volume flow changes by means of, at least, one heat exchanger with lower priority. At the larger difference of medium temperatures in the supply and return pipelines the volume flow changes by means of mixing of the medium which enters the return pipeline from all heat exchangers of the heating unit, the medium temperature in the return pipeline is regulated to the value optimum for the heating device of the heating unit.

EFFECT: possibility to maintain medium temperature in the return pipeline of the whole installation at the favourable level at adverse power parameters.

8 cl, 1 dwg

Description

FIELD OF THE INVENTION

The invention relates to a method for controlling the volumetric flow of a heating and / or cooling medium flowing through heat exchangers in a heating or cooling installation, in which the target difference in the temperature of the medium in the supply and return pipelines of the individual heat exchangers is respectively controlled by means of an adjustable and / or fixed restriction of the corresponding heat exchanger valve.

State of the art

Such methods are usually applied in order to limit the maximum value of the flow rate of the medium that flows through the individual heat exchangers and is controlled by the user with the help of the heat exchanger valve in heating plants, which, if the valves are fully open, the heating medium is It fills all heat exchangers in such a way that in all heat exchangers the same difference in the temperature of the medium is formed in the supply and return pipelines (hydraulic alignment). The reason that the heating medium acts differently is because the fluid flow, flowing through the pipelines from the pump to the individual heat exchangers, experiences hydraulic resistance, which can vary significantly in different areas due to the use of pipes of different diameters and lengths and as a result the availability of bends.

Under the heat exchangers in the present invention refers to heating devices, i.e. radiators, as well as cooling devices, such as air conditioning units, in which indoor air is heated or cooled. The difference in the temperature of the medium in the supply and return pipelines in the corresponding technical field refers to the temperature difference of the heating medium in the supply and return pipelines, which is formed if the heating medium flows through the heat exchanger and at the same time transfers heat to the heated or cooled room. In the present description, for the sake of simplicity, in most cases we are talking about heating, although it always means and also implies the case of cooling the room.

The difference in the temperature of the medium in the supply and return pipelines depends, inter alia, on the one hand, on the temperature of the medium surrounding the heat exchanger, and on the other hand, on how large is the flow rate of the heating medium flowing through the heat exchanger, since, as easy to understand at high flow rates, i.e. with a short residence time in the heat exchanger, the medium cools relatively little, and at a low flow rate, i.e. with a relatively long residence time of the medium in the heat exchanger, a relatively strong cooling of the medium in the heat exchanger occurs. At a high flow rate through the heat exchanger, which at the same time means that the temperature difference between the supply and return pipelines is small, the heat exchanger works with high heat output, since the entire heating surface of the heat exchanger is used, and thus a lot of heat is removed to the environment.

In order to ensure the efficient use of the heating installation, depending on the heating device, one should strive to ensure that a heating medium with a certain temperature enters from the return pipe into the heating device, and mainly strive to ensure that the temperature of the medium is opportunities lower. If the temperature of the medium in the return pipe is below 35 ° C, this factor may turn out to be unfavorable only in the case of steel heating boilers, because the condensation of water vapor contained in the exhaust gas may cause the formation of corrosion. However, in modern heating devices, on the contrary, it is necessary that the temperature of the medium in the return pipe be low, since in this case the moisture contained in the exhaust gas is condensed on the corresponding heat exchanger, and the heat obtained by condensation can be used to heat the heating medium.

The aforementioned hydraulic alignment according to the difference in the temperature of the medium in the supply and return pipelines, which is identical for all heat exchangers of the heating installation, is effective only if each room, i.e. the area of the heated object is actually equipped with heat exchangers with optimal power. However, in practice, this never happens, since the installation of heat exchangers takes into account not only their power, but also aesthetic aspects, and in particular, their actual presence at the time of installation plays a large role at the final stage of construction of the facility. In addition, heat exchangers are designed for certain fixed power values. This leads to the fact that in practice there are very rare situations when heat exchangers with optimal power are installed in the room or in the area, so that hydraulic alignment in accordance with the prior art for the identical difference in the temperature of the medium in the supply and return pipelines for all heat exchangers is not manages to combine with real technical requirements. In addition, heating plants are installed, first of all, in individual zones, as a rule, without taking into account energy efficiency, and the user controls the valves of the heat exchangers, i.e. thermostat heads, for a short time in accordance with the subjective sensations of cold, so that often individual heat exchangers require extremely high heat output, while in other areas very low temperatures are chosen for the purpose of apparent savings. However, particularly low temperatures in rooms located near high-temperature rooms lead to heat loss in high-temperature rooms (primarily with open doors), so in order to maintain the required temperature in such rooms, heat exchangers with very high heat output, which generally increases the temperature of the medium in the return pipe of the system and thereby reduces the efficiency of the heating installation.

Disclosure of invention

Thus, it is an object of the present invention to provide a control method, i.e. hydraulic alignment of the heat exchangers of the heating installation, allowing to take into account the user's requirements, in which the heat exchangers operate with lower or higher power values, i.e. with energy-unfavorable parameters, which at the same time will allow maintaining the temperature of the medium in the return pipe of the entire installation at a favorable level.

To solve this problem, in accordance with the invention, different priorities are set in the method for heat exchangers, and based on the target temperature difference of the medium in the supply and return pipelines, in this installation for heat exchangers with a higher priority, a smaller target difference in the temperature of the medium in the supply and return pipelines is allowed, and for heat exchangers with a lower priority, a large target difference in the temperature of the medium in the supply and return pipelines is provided, and in which of a heat exchanger with a higher priority with a smaller difference in the temperature of the medium in the supply and return pipelines, the volume flow is changed by means of at least one heat exchanger with a lower priority with a larger difference in the temperature of the medium in the supply and return pipelines so that by mixing the medium that enters to the return pipe from all heat exchangers of the heating installation, the temperature of the medium in the return pipe is adjusted to the optimum for the heating device and a heating installation values.

The method proposed in the invention thus defines heat exchangers with higher priority, such heat exchangers that constantly or periodically require a heat output that is higher than the heat output that can be achieved by observing the target temperature difference specific to a given installation media in the supply and return pipelines. This is done, for example, if in a room, i.e. zone, to ensure the necessary heat output there is one or several heat exchangers with lower power installed, or if one user wants to provide quick heating for a short time and for this purpose opens the heat exchanger valve wide. In order to compensate for the excess heat that enters the return pipe from heat exchangers operating in this way to ensure the optimum return temperature of the heating installation, the method proposed in the invention now proposes to define known heat exchangers as heat exchangers with a lower priority, and for such heat exchangers provides a very large difference in the temperature of the medium in the supply and return pipelines, which should be greater than the target temperature difference ur environment in the supply and return piping specific to the installation. Heat exchangers of this kind are, for example, heat exchangers that are installed indoors, i.e. zones, and which are selected with more power than is necessary for heating a given room, or heat exchangers in zones in which a high heating speed is not required, or in such rooms in which heat should provide only minimal heating to a given temperature. In this regard, such premises include cellars and amateur workshops, heated garages, sports halls, utility rooms and similar areas of objects. In such zones, it is possible to put up with a very large difference in the temperature of the medium in the supply and return pipelines, since in such zones, as a rule, fast heating is not required, and it is enough that a certain amount of heat is supplied to them at a certain time of day, so that to prevent complete cooling of the room. By using heat exchangers with a lower priority with a large temperature difference, i.e. with very low ambient temperatures in the return pipe, a relatively cold medium is fed into the return pipe, which is mixed in the return pipe of the heating installation with hot heating medium from heat exchangers with a higher priority, so that the temperature is balanced, and generally acceptable low temperature, and the unit can operate efficiently even though individual heat exchangers have been selected with higher and lower values power. Thus, the invention proceeds from the above concept of hydraulic alignment, according to which, the known various differences in the temperature of the medium in the supply and return pipes can be controlled and also fixed by means of an appropriate limiter so that the values of the deviations from the target temperature difference indicated on the nameplate with technical data are compensated heat exchangers of the heating installation using all heating surfaces of the heating installation, resulting Why not even optimally designed heating installations, which, for example, can often be seen in old houses, can work quite efficiently.

Accordingly, the really achieved target temperature difference of the medium in the supply and return pipelines depends on how many heating devices work after adjustment, since after the user closes the heat exchanger valves, the volume flow, and therefore the flow pressure, in the heat exchangers remaining, increases and thus the target temperature difference of the medium in the supply and return pipelines may again fall to a level below the minimum allowable. This effect can be seen with different control of the heating pump feed pump. However, in the simplest case, in accordance with the invention, the required alignment is also achieved if the target temperature difference of the medium in the supply and return pipelines is provided in the corresponding heating devices for the case when all the valves of the heat exchanger are open.

In a preferred embodiment of the present invention, the difference in the temperature of the medium in the supply and return pipelines for heat exchangers with a lower priority is selected so large that the temperature control of the medium in the return piping is performed in such a way that the specific temperature difference in the supply and return pipelines for this installation is achieved . For a specific target temperature difference of the environment in the supply and return piping, corresponding heating devices, for example, such as a gas or liquid fuel burner, wood chip heating devices, and other heat sources, such as district heating systems , can work with optimal energy parameters, so that the used energy carriers can be used in the best way.

The implementation of the method proposed in the invention is facilitated if the operating parameters are taken into account on all heat exchangers, i.e. the heating surfaces of the object, and to achieve the desired effect, in accordance with the invention, the optimum temperature of the medium in the return pipe is achieved, for example, the amount of heat and heat loads can be recorded or determined; those. excess heat from heat exchangers with a higher priority can, accordingly, be used economically in heat exchangers with a lower priority. In order to ensure that such an event is carried out quickly and with control in practice, the method proposed in the invention is preferably carried out in such a way that the temperature values of the medium in the supply and return pipes of the individual heat exchangers are recorded and transmitted to the central processor, which determines the magnitude of the regulatory action for the controlled and / or a fixed restriction of all valves of the heat exchangers and transmits them in the form of a control signal to the valves of the heat exchangers with removable actuating motors. For this purpose, temperature sensors are installed on the heat exchangers on the supply side and on the reverse side of the heat exchanger, which transmit the measured values to the central processor wirelessly or without cable connection. There, these values are compared with the set values, and after a certain interval of time out, a command is sent for the next switch. Alternatively, the amount of heat that is removed from the individual heat exchangers to the return flow is calculated in a known manner in the central processor, moreover, the corresponding adjustment of adjustable and / or fixed restrictions on the valves of the heat exchangers, i.e. thermostat heads are made using actuators, i.e. engine heads. After the alignment of the system in accordance with the method proposed in the invention, the magnitude of the regulatory action can either be fixed manually using mechanical stops, or recorded in the processors of the executive motors. If the magnitude of the control action that limits the flow rate through the valves of the heat exchanger is adjusted, the engine heads can either be removed or left on the heat exchangers. The central processor may record data that can be used, for example, to perform calculations of energy consumption. However, this data can be read remotely in a particularly preferred way.

As already mentioned, the classification of the heat exchanger as a heat exchanger with a higher or lower priority can be carried out taking into account whether the corresponding heat exchanger with a higher or lower power is selected for this zone. However, priority setting can also be performed in a dynamic mode, and it is preferable to act in such a way that when calculating the magnitude of the regulatory effect of at least one heat exchanger with a higher or lower priority, the measured value of the external temperature is taken into account.

If the aforementioned actuators, i.e. the engine heads are located on heat exchangers, it is possible to provide a particularly favorable adaptive principle of operation of the heating installation, with the help of which in separate rooms, i.e. zones, individual heat exchangers can also be implemented in accordance with the user's time requirements. For example, the method can be performed preferably in such a way that, if a temporary working requirement is made to reduce the difference in the temperature of the medium in the supply and return pipelines on the corresponding heat exchanger, then this heat exchanger is given a certain priority, as a result of which the volumetric temperature equalization in the return pipe of the heating installation the flow of the heating medium is reduced by means of at least one heat exchanger with a lower priority. By dynamically changing the priorities of the individual heat exchangers, it is possible to reduce the volume flow in a known area of the object by means of a heat exchanger in such a way that as a result of the thus increased difference in the temperature of the medium in the supply and return pipes, a cold medium is formed on these heat exchangers in the return pipe. Since the amount of medium in the return pipe and coming from heat exchangers that operate at a large temperature difference, i.e. at a low flow rate, it is relatively small, as a rule, in order to equalize the excess heat that enters the return flow from a heat exchanger operating at too low a temperature difference, several heat exchangers with a large temperature difference must be used to ensure that a sufficiently cold medium enters the return pipe.

If, for example, at a certain time of the day, at which the object was previously heated a little, the user unexpectedly wants to provide space heating, for example, quickly warm the work room at night, then as a result a very small difference in the temperature of the medium in the supply and return will be established on the corresponding heat exchanger pipelines. In this case, the method proposed in the invention can preferably be performed in such a way that when the heat exchanger is temporarily turned on, which leads to a decrease in the difference in the temperature of the medium in the supply and return pipelines on the corresponding heat exchanger, a certain priority is assigned to this heat exchanger, as a result, to equalize the temperature of the medium in the return pipe of the heating installation, the flow of the heating medium is increased by at least one heat exchanger with a lower priority. This event, of course, leads, as is easily understood, to the fact that the difference in the temperature of the medium in the supply and return pipelines in this lower-priority heat exchanger decreases as a result, however, by increasing the flow rate, cold medium in the return piping can leave this heat exchanger, which generally favorably affects the efficiency of the heating installation. Thus, at least one heat exchanger again operates with a large temperature difference so that as a result the optimum temperature of the medium in the return pipe is established. In this case, priorities are set in dynamic mode and transferred to the central processor. The central processor assigns a heat exchanger from which a higher heat output is required, a higher priority, and by appropriate activation of the actuating motors sets a small difference in the temperature of the medium in the supply and return pipelines and thereby a high heat output on the corresponding heat exchanger. This heat exchanger subsequently delivers an unfavorably hot return medium to the return line of the heating installation, whereby a preferred method is to increase the flow rate through one or more lower-priority heat exchangers. In this case, the heat exchanger with a lower priority again becomes the heat exchanger in the room, where although a specific heat output is not directly required, however, to increase the overall efficiency of the installation, the flow rate is increased by means of similar heat exchangers with a lower priority, so that by cooling the medium in the return pipe with coming from this zone of the medium in the return pipe increases the efficiency of the coolant in the device for heat production. In this case, the preferred method can even be performed in such a way that not only the existing flow rate in the heat exchanger with a lower priority increases, but even the heat exchanger is turned on, which has been turned off at a given time, which is again performed by the corresponding setting signal of the central processor on the corresponding executive engines i.e. engine heads.

In accordance with a preferred embodiment of the method proposed in the invention, it is thus operated in such a way that the user’s temporary requirement is met by entering the setpoint of the room temperature, that the setpoint is sent to the central processor and that the control action values are calculated in the central processor for one or more heat exchangers and are transmitted in the form of a setting signal to the actuator valves of the heat exchange valves nicknames.

The invention is explained in more detail below by the execution drawings.

Brief Description of the Drawing

Figure 1 presents a schematic illustration of a heating installation to perform the proposed invention.

The implementation of the invention

The heating installation is indicated in FIG. 1 by the number 1. The heating installation 1 comprises a heating device 2 and a series of heat exchangers 3 and 4. Heat exchangers 3 and 4 are connected in parallel between the supply pipe 5 and the return pipe 6. The number 7 indicates a pump for supplying a heating medium. The valves 8 of the heat exchangers 3 and 4 are controlled directly by means of actuators, i.e. engine heads 9 and can be fixed in any position with the help of stops. The executive motors 9 are connected wirelessly or via cables to the central processor 10, which receives and processes the data received from the temperature sensors 11 in the supply pipe and from the temperature sensors 12 in the return pipe of the individual heat exchangers and recorded by room temperature sensors in the room. The central processor, in addition, in the ideal case, contains data on the temperature of the medium in the supply pipe entering the heating device, the rotation speed of the pump and the external temperature, as well as the temperature in the correspondingly heated rooms, i.e. areas.

When carrying out the method proposed in the invention, heat exchangers 3 are defined, for example, as heat exchangers with a higher priority, and heat exchangers 4 as heat exchangers with a lower priority. As mentioned above, this may be due to the selection of heat exchangers with a higher or lower power, or may be performed as a result of the temporary activation of the heat exchangers by the user. If now heat exchangers 3 for these reasons operate with a smaller difference in the temperature of the medium in the supply and return pipes, that is, with a higher temperature of the medium in the return pipe, then a relatively hot heating medium enters the return pipe 6, which could lead to an unfavorably high temperature of the medium in the return pipe in the heating device 2. In order to prevent this, at least one of the heat exchangers 4, that is, one heat exchanger with a lower priority with a very large difference in the temperature of the medium in the supply and return pipelines in order to supply a certain amount of cold heating medium to the return pipe 6 and thereby, accordingly, reduce the temperature of the medium in the return pipe in the heating device 2.

The difference in the temperature of the medium in the supply and return pipelines in individual heat exchangers is regulated by means of flow control, and this adjustment is based on the setting signals that the central processor 10 transmits to the executive motors, i.e. on engine heads 9.

If now the user additionally turns on one or several heat exchangers 3 with even greater heat output, i.e. with an even smaller difference in the temperature of the medium in the supply and return pipelines, then using the system proposed in the invention it is possible to carry out equalization so that, for example, the flow rate is reduced by one or more heat exchangers 4 by means of actuators, so that the temperature of the medium in the return piping in direction to the heating device 2 was maintained at the required level.

In the case of applying the less expensive principle of operation, only removable executive motors are used, with which you can once adjust the maximum flow rate through separate heat exchangers, after which the adjustment positions calculated by the central processor can be limited by mechanical stops, and the executive motors can be removed and installed again thermostatic heads.

Claims (8)

1. A method for controlling the volumetric flow of a heating and / or cooling medium flowing through heat exchangers in a heating or cooling installation, in which the target difference in the temperature of the medium in the supply and return pipes of the individual heat exchangers, respectively, is controlled by means of an adjustable and / or fixed restriction of the corresponding heat exchanger valve, characterized in that the heat exchangers are assigned different priorities, moreover, based on the temperature difference of the medium specific to a given installation, the supply and return pipelines for heat exchangers with a higher priority allow a smaller target difference in the temperature of the medium in the supply and return pipelines, and for heat exchangers with a lower priority it provides a large target difference in the temperature of the media in the supply and return pipelines, while using a heat exchanger with a higher priority with a smaller difference in the temperature of the medium in the supply and return pipelines, the volume flow is changed by means of at least one heat exchanger with a lower priority for a larger difference in the temperature of the medium in the supply and return pipes so that by mixing the medium that enters the return pipe from all the heat exchangers of the heating installation, the temperature of the medium in the return pipe is adjusted to the optimum value for the heating device of the heating installation. 2. The method according to claim 1, characterized in that the regulation of the temperature of the medium in the return pipe is performed in such a way that a target-specific difference in the temperature of the medium in the supply and return pipelines is achieved. 3. The method according to claim 1 or 2, characterized in that the temperature values of the medium in the supply and return pipes of the individual heat exchangers are recorded and transmitted to the central processor, which determines the magnitude of the regulatory action for the adjustable and / or fixed restriction of all valves of the heat exchangers and transmits them in the form of a control signal to the valves of heat exchangers with removable actuators. 4. The method according to claim 3, characterized in that to calculate the magnitude of the regulatory action, the amount of heat transferred from the respective heat exchangers to the return pipe and the increased amount of heat generated in the heat exchangers at a higher priority due to the small difference in the temperature of the medium in the supply and return pipelines are compensated by adjusting at least one heat exchanger with a lower priority with a large temperature difference. 5. The method according to claim 3, characterized in that when calculating the magnitude of the regulatory effect of at least one heat exchanger with a higher or lower priority, take into account the measured value of the external temperature. 6. The method according to claim 1, characterized in that upon presentation of a temporary working requirement to reduce the temperature difference of the medium in the supply and return pipelines on the corresponding heat exchanger, this heat exchanger is assigned a certain priority, as a result of which volumetric alignment of the medium temperature in the return piping of the heating installation the flow of the heating medium is reduced by means of at least one heat exchanger with a lower priority. 7. The method according to claim 1, characterized in that if a temporary working requirement is made to reduce the temperature difference of the medium in the supply and return pipelines on the corresponding heat exchanger, then this heat exchanger is given a certain priority, as a result of which volumetric alignment of the temperature of the medium in the return pipe of the heating installation the flow of the heating medium is increased by means of at least one heat exchanger with a lower priority. 8. The method according to one of claims 4 to 7, characterized in that the time requirement of the user is fulfilled by entering the setpoint of the room temperature, the setpoint being sent to the central processor, while the values of the control action are calculated in the central processor for one or more located heat exchangers and transmit in the form of a setting signal to the actuator valves of the heat exchangers.

Images